7 Calculating CostSuppose your local electric company charges 7¢ per kilowatt hour of electricity. If your TV consumes (uses) at a rate of 200 watts, and the TV is on for 150 hours on average a month, how much would the monthly cost of power for the television be?

8 Calculating Cost First, change the watts into kilowatts.200 W = 0.2 kW  Divide by 1000Next, multiply the number of kilowatts by the number of hours the TV runs.0.2 kW x 150 h = 30 kWhLast, multiply the number of kilowatt hours by the cost per kilowatt hour.30 kWh x $0.07/ kWh = $ 2.10Monthly cost for TV power

9 Homework On one day, a household used a dryer for 2 hours,a colour TV for 4 hours, a vacuum cleaner for 1hour, and a toaster for 0.2 hours.a) What was the total energy these appliances consumed that day?b) If electrical energy costs 7¢/(kWh), what was the total cost of the energy used by these appliances on that day?